code: def gpus_for_testing():
      """For the moment it's very simple, but it might change in the future,
      with multiple physical gpus for example. So it's better if this function
      is called rather than hardcoding the gpu devices in the tests.
      """
      if not is_gpu_available():
          raise SystemError(
              "You are trying to get some gpus for testing but no gpu is available on "
              "your system. \nDid you forget to use `@pytest.mark.needs_gpu` on your test"
              " so that it's skipped automatically when no gpu is available?"
          )
      return ["gpu:0", "gpu:1"]
  
imports: import os
  import random
  import inspect
  import numpy
  import pytest
  import tensorflow
  from tensorflow_addons import options
  from tensorflow_addons.utils import resource_loader
  from tensorflow_addons.utils.tf_test_utils import layer_test
label_desc: Use image node_id 11 for calling a global function with example usage: gpus_for_testing() and returns: list